Electric motors for motor vehicle actuator drives are already known. They are used, for example, as window lifter motors, as a drive motor for adjusting the push and tilt sunroof or for assisting the steering process of a motor vehicle. A specific design of such a motor is, for example, a brushless commutated motor with an internal rotor and an electrically excited stator. Such a motor generally has a motor housing, a stator assembly which is inserted into the motor housing and has wound stator teeth, and a rotor assembly which is inserted concentrically into the motor housing, within the stator assembly. The rotor assembly includes a rotor shaft and a rotor packet which is attached to the rotor shaft. Depending on the design, the rotor assembly can also be excited electrically with windings or be equipped as a permanently excited rotor with permanent magnets. The attachment of the stator assembly in the motor housing is done in many known motors by bonding or introducing a sealing compound which, in the cured state, permanently connects the stator assembly to the motor housing. A disadvantage of attachment of the stator assembly in the motor housing by bonding or by using a sealing compound is that disassembly of the respective motor, for example for repair purposes, is not possible without damaging it.
A further possibility for the connection of a stator of an electric motor to a motor housing is shown, for example, by the German laid-open patent application DE 102 57 889 A1. In this connection, the stator is introduced coaxially into the motor housing and said motor housing engages around it. For the purpose of attachment, at least one clip is introduced between the stator and the motor housing in order to clamp the stator in the motor housing. The clips form here a tangential wedge connection of the stator to the housing.
The German laid-open patent application DE 102 61 617 A1 discloses an electrical machine having a housing and a stator packet which is arranged in the housing. The housing and the stator packet are clamped to one another by means of sprung clamping means. In this context, play between the housing and the stator packet which is present and which is due to fabrication is compensated by using the sprung clamping means which are arranged between the housing and the stator packet.
The insertion of clamping means between the housing wall and the stator means that the clamping means apply, as it were in a punctiform fashion, a force to the housing wall in a radial direction. As a result, there is the risk of the housing wall and surface of the stator being pressed apart from one another and of a gap forming between them. The housing wall is frequently provided to guide the magnetic flux as part of the stator yoke. In this case, air gaps which are produced between the housing wall and the stator are very disruptive. The transfer of heat from the stator to the housing and from there to the outside is also impeded by air gaps between the stator and the housing, and this in turn has an adverse effect on the power of the electric motor.